All low-fat or reduced-fat spreads contain less fat than butter or standard block margarine and a great deal more water. This means that while they can be used like butter or margarine as a spread on bread and so forth, they are not always suitable for cooking. They can be used successfully for all-in-one sauces and cakes, for choux pastry and, if mixed with full-fat butter or block margarine, can sometimes be used for other pastry. To make a cheesecake base, normally done by mixing butter with biscuit crumbs, melt the low-fat spread carefully over a low heat and then add the crumbs.

Low-fat spreads are generally not suitable for shallow or deep-fat frying because they contain too much water. However, they can be used in a nonstick saucepan to fry foods such as onions or mushrooms, as long as it is gently done over a low heat. They are also unsuitable for traditional biscuits and cakes, and preserves such as lemon curd, because they do not set firm.

Very low-fat spreads, which have an even higher proportion of water and contain less than 25 percent fat, are quite unsuitable for frying or sauteing because they will spit and are liable to burn very easily.

In general, softer cheeses have a lower fat content than hard cheeses because they have a higher percentage of water. Cream cheeses and cheeses labeled double and triple cream are the exceptions as they are particularly high in fat, containing about 47 percent fat. Hard cheeses made from goat's and ewe's milk are likely to be higher in fat than similar cheeses made from cow's milk, as both goat's and ewe's milk have a naturally higher fat content.

If you are aiming to cut down on your fat intake, it is best to stay with cottage cheese or soft, fresh cheeses such as ricotta and feta. Of the harder cheeses, Edam is a better low-fat choice than Cheddar. Some cheese varieties can be found in reduced-fat versions. These include Edam, Swiss, Cheddar, cream and mozzarella.

Some supermarkets stock a selection of lower-fat alternatives to full-fat cheese in which the saturated butter fat has been removed and replaced with polyunsaturated vegetable oils. These cheeses are particularly useful for those people who want to reduce their saturated fat intake. The nutritional information supplied by manufacturers can be misleading. The fat content is often expressed as 'fat in dry matter', which means the fat content of the cheese solids after the water has been removed. An ordinary Brie which is labeled a '60 percent' Brie is not as rich as it sounds because it actually contains half the fat of a regular cream cheese.